There are different parts of a katana and many points of appreciation. The curve of the "mune" is one of the most easily recognizable aspects of the overall shape of a katana. This section presents the types of munes, what can be understood by their shape, and anecdotes related to munes.
Mune de Katana : definition
The mune is the back of the blade, the non-bladed side of the blade. The mune is also known as the "spike", and the use of the side without the blade to strike the opponent without cutting is called "mune-uchi".
Katanas are nowadays mainly used to be appreciated as "art swords", but in the past they were used as weapons. Japanese swords are essentially characterized by the fact that they are not double-edged, but have only one blade on one side. Although double-edged swords appear to be more powerful, there are also advantages to single-edged swords.
For example, with a single-edged blade, there is no risk of being injured by the blade facing you in a mutual sword fight, and by placing your hand on the mune, which is on the opposite side of the blade, you can cut with your weight.
"Stealing the mune", is an expression that refers to the construction in which the layers of the mune are extremely thin compared to the layers (thickness) of the shinogi-suji section of a katana. This is one of the characteristics of the Katana Yamatoden.
This type of shape is also part of the sword blade shapes "Shobu-zukuri", "Kanmuri-otoshi zukuri" and "Unokubi-zukuri". The purpose is to make the blade lighter and to increase the strength and resilience of the material, but also to make it easier for the blade to pass through when cutting.
Types of mune on katanas
Munes are generally classified into four types based on the shape of their cross section called:
- mitsumune (true mune)
- marumune (grass mune)
- kakumune (square mune)
- iorimune (line mune)
These types are important when looking at katanas, because it is possible to deduce the period in which they were made. We present here the characteristics of each of them.
The mitsumune is a trapezoidal-shaped mune, so named because it has three sides, and is also known as a "shinomune". From the Heian period (794-1185), it became the main type of sword along with the hermitage, and was made throughout the Koto and Shintō periods. It is often found on Yamashiro-den and Soshu-den swords and daggers.
It is a ridge with a semi-circular section and is often found on swords from the Kyushu and Hokuriku regions.
Kakumune, also known as Hiramune, is a flat mune without ridges at the top.
It is the oldest form of mune and is common in Kamiko swords.
The iorimune, also known as gyou no mune, is often found on large swords and is formed so that the top of the mune is at an acute angle.
The height of the mound is called "hermitage", and a steeply sloping mound is called a "high hermitage", while a low sloping mound is called a "low hermitage".
How thick are the layers of the mound?
The thickness of a katana when it is arranged vertically and seen from the mound, i.e. the thickness of the mound, is called "superposition". If the thickness is measured by mune, it is called mune-zukuri, and if it is measured by shinogi, it is called shinogi-june. Shinogi refers to the high, mountain-like ridges on the side of the blade (between the blade and the mune) that appear on a sword with a shinogi-zukuri structure.
It is said that the shinogi was created to make the blade thinner for a better edge and to further reduce impact. The shinogi goes from yokote-suji to mune-machi in the center of the blade, and is called shinogi-suji, while the surface between shinogi-suji and mune is called shinogi-ji. Moreover, even today, the term "shinogi-sharu" is used to describe a fierce fight, and is derived from the shinogi of a sword. The advantage of thin-layer katanas is that they are sharp, but the disadvantage is that they tend to bend easily.
How to check the thickness of the covering?
To check the thickness of the overlap, hold the katana upright with the mune facing you, and see how the ridges of the edges protrude to the left and right of the mune.
The difference between the thickness of the cover and the width of the body
The width of the blade is usually defined at the tip of the blade. If the mune is not included in the width of the body, one risks making a katana that does not fit into the scabbard.
Yamatoden katanas have not only a high Shinogi but also a wide body width, while katanas of the Soshu and Bizen styles have a relatively low Shinogi and a wide body width.
The width and layering of the handle are called motohaba and motokasane respectively, while the width and layering of the tip are called sakihaba and sakikasane. The overlap is usually about 7 mm at the base and 5 mm at the tip.
The relationship between width and overlap changes over time.
During the Kamakura (1192-1333) and Nanbokucho (1392-1333) periods, the difference between the width of the tip and the original width began to decrease. When considering the changes in width, it is also important to pay attention to the relationship with the stratification of the sword to get a more detailed picture of the period in which it was made.
The balance between the shape of the mune and the thickness of the layering, etc., changes the beauty and feel of the katana.
Thus, the balance between the height of the "Shinogi", the width of the body, the shape of the "Mune" and the thickness of the layers has a great influence not only on the overall impression and beauty of the katana, but also on the feel of the katana when it is actually used.
Did the practice of "Mune-uchi" really exist?
"Mune-uchi" refers to hitting with the back of the blade, where the blade is not present, to get rid of an opponent without killing him with the katana.
In historical dramas and television comedies, when a fighter thinks he has taken down his enemy, he is told, "Don't worry, it's a Mune-uchi. You won't die!" and defeat your opponent without killing him.
Mune-uchi here refers to a technique where, after drawing the katana, the blade of the katana is turned upwards and the chain is reversed so as not to fracture or mortally wound the enemy, and the blade is swung downwards with the mune side down.
Few cases of Mune-uchi actually used.
However, this Mune-uchi, in practice, is not possible, and samurais do not draw their katanas if they want to hit their enemies without killing them. Indeed, if a samurai used a sword, it always meant that he would kill the enemy and end the fight.
Originally, katanas were not made to be hit with the point, and some people thought that if you hit a hard object with the point, the blade might break, and that there was no need to hit the point in the first place.
The "mune-uchi" is not safe
If the blade is turned around and the point is directed at the opponent, there is a risk that he will realize that you do not intend to kill him and will cut you in the opposite direction.
Another aspect is that the blade is held in the opposite direction to normal, which shifts the center of gravity and makes it difficult to use.
In the historical drama, the katana is drawn and the blade is held upside down and struck at the tip so that the viewer can clearly see that it is a Mune-uchi, but originally the correct way was to "turn the blade over just before it reaches the opponent's body in an attempt to slice him normally". In other words, the purpose of the Mune-uchi is not to actually hit, but to make the opponent think that he has been cut and to make him lose consciousness.
However, since the katana is quite heavy, there is a risk of actually hitting, which could result in a broken bone or, in the worst case, a fatal injury, depending on the force applied, and thus deviates from the true intention of Mune-uchi, which is what it should be. Therefore, there are few actual instances of Mune-uchi being used, and even if it were, it would not be safe.